Ultrasonic Wave & Magnet

Magnetic

Kyungwon Industry is Korean piezoelectric ceramic manufacturer which research and develop in piezoelectric magnetic field and utilize magnet technology


What is a magnet?

A magnet is the source substance that generates a bipolar magnetic field with two poles.

It exists a lot around us and attracts magnetic substances, such as iron. When magnets are close together, opposite poles attract while the same poles repel.
When you place a magnet close to another one, they stick together. This is a common fact that even elementary school students know, but many people do not understand why magnets stick together.

The reason why magnets stick together lies in the atom, the minimum unit of every substance. Electrons revolve around the atom and thess electrons' revolution exhibits the force of attraction.
A substance with a unified direction of force of attraction has a magnetic force (force of attraction).
On the other hand, if individual atoms' direction of force of attraction is different from each other, the substance cannot have a magnetic force.
A substance of which atoms have unified direction of force of attraction can be said to have a magnetic force.

Types of Magnet

Type Image Pros Characteristic
Permanent Magnet The object itself has magnetic property and has the ability to attract magnetic substances, such as iron.
It is sometimes called "hard magnetic material" and must have the N and S poles simultaneously.
Electromagnet It is a magnet, also called soft magnetic material, that temporarily generates magnetic force by winding a coil around a magnetic core and energizing it.
Ferrite Since it is a sintered magnet, it is highly corrosion and oxidation resistant, and has high magnetic retention power. Therefore, it is stable, does not demagnetized easily, and the cheapest. It is mechanically weak and cracks easily.
Alnico This magnet has the best temperature characteristics and is suitable for high-temperature environments.
In addition, it is mechanically strong. 		It has weak magnetic retention power and demagnetizes easily. It needs to have a long distance between poles and an elongated shape.
Samarium Cobalt Its magnetic energy is comparable to neodymium magnet.
It has excellent temperature characteristics and is suitable for high-temperature environments. It is also highly rust-resistant. 		It rusts easily, so its surface is generally treated with plating. It has low-temperature characteristics and is weak to heat. It is more expensive than any other magnets,
and has low mechanical strength, so it is brittle and requires attention.
Neodymium It has the best magnetic property among commercially available magnets, and generates a strong magnetic field even if it is small in size. It is rigid and does not crack or stick easily, and has excellent mechanical strength. It rusts easily, so its surface is generally treated with plating. It has low-temperature characteristics and is weak to heat.